JP3448696B2 - Thermal transfer recording medium - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording medium used in, for example, a thermal transfer recording type printer.

[0002]

2. Description of the Related Art In recent years, thermal transfer recording type printers having advantages such as "easy maintenance" and "low noise" have been widely used. The thermal transfer recording medium used in this system is one in which an ink layer is formed on a film-shaped support, and the above ink can be recorded on a transfer-receiving member such as paper or a plastic film by the heat of a thermal head. .

Conventionally, in this type of thermal transfer recording medium, since a heat-melting substance composed mainly of waxes having a small polarity has been used as a material for the ink layer, polyester which is widely used as a support for thermal transfer recording. However, there is a drawback that a sufficient adhesive force cannot be obtained between a highly polar plastic film such as polyimide or polycarbonate. For this reason, when mounting such a thermal transfer recording medium in a printer, the ink layer may fall out due to the wrinkles or folds of the support or the trailing during printing (being dragged by the original transfer portion The phenomenon that the ink layer is also transferred) occurred. Therefore, in recent years, in order to increase the adhesive force between the support and the ink layer, it has been proposed to form a primer layer between them.

[0004]

However, such a conventional example has the following problems. That is, when the resin-based primer is used, the adhesive force between the support and the ink layer is improved, but when the printing speed is high and the printing environment is as high as about 40 ° C., clinging or sticking may occur. Jerk occurs. In other words, the ink layer transfers to the transferred material, but does not separate from the support, so that the transferred material and the thermal transfer recording medium are conveyed as a single body and may be caught by the winding shaft. ), The ink layer is not smoothly peeled off from the support and is intermittently peeled off, and as a result, horizontal streaks are formed on the recorded matter (jerk).

As a result of investigation by the present inventors, these phenomena were caused by the following reasons. That is, since printing occurs when the ink layer is peeled from the support, a high printing speed means a high peeling speed in terms of rheology. Then, as a result, a large peeling force is generated between the ink layer and the support, so that the ink layer is not peeled off from the support, which causes the above-mentioned sticking and jerk.

Further, when the ambient temperature is high, the resin of the primer layer softens and fits well with the ink layer. Therefore, in order to transfer the ink layer, the primer layer must be cohesively destroyed, and as a result, A large peeling force is required to peel the ink layer from the support. As described above, in the conventional technique, smooth printing cannot be performed when the printing speed is fast or when printing is performed in a high temperature atmosphere.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a thermal transfer recording medium capable of high-speed printing and smooth printing in a high temperature atmosphere.

[0008]

The present invention provides a thermal transfer recording medium in which an ink layer containing a heat-fusible substance is formed on a support through a primer layer.
Caprolactone type oligomers including prolactone type oligomers
Rigomers are characterized by having a number average molecular weight of 8,000 to 10,000 .

As the support of the present invention, a plastic film which is generally used in this type of thermal transfer recording medium can be used, and examples thereof include a polyester film, a polyimide film, a polysulfone film, a polypropylene film and a polycarbonate film. . Also, a condenser film can be used.

The primer layer of the present invention contains a caprolactone-based oligomer. The caprolactone-based oligomer has the following chemical structural formula

[Chemical 1] It can be obtained by polymerizing a cyclic ester monomer having ## STR4 ## but it is also possible to use a derivative such as caprolactone diol or caprolactone triol produced by modification of another organic compound.

The caprolactone-based oligomer may be used alone or as a mixture of two or more, but it is preferable that the number average molecular weight thereof be 8,000 to 10,000 .
When it is larger than this value, the ink layer does not undergo cohesive failure when peeled from the support, and sticking or jerk occurs.

In the primer layer of the present invention, a heat-melting substance such as wax and the like, a thermoplastic substance, a tackifier, a softening agent, etc. are used for the purpose of adjusting the viscosity and for other purposes, for example, adjusting the peeling force and the ink layer. It can be appropriately selected and blended for transferability, but the caprolactone-based oligomer must be contained in the entire primer layer in an amount of 30% or more. Three
If it is less than 0%, the effect of the present invention is hard to occur. It is desirable that the heat-fusible substances such as waxes be selected from the group consisting of carnauba wax, candelilla wax, polyethylene wax, paraffin wax, microcrystalline wax, fatty acid ester, and fatty acid amide. The thermoplastic material is preferably selected from the group consisting of polyester resin, acrylic resin, terpene resin, styrene resin, rosin resin, petroleum resin, and rubber resin, for example. Further, a colorant such as a pigment or a dye, a filler or the like can be added.

The primer layer has a thickness of 0.2-1.
It is provided in a range of 5 μm, preferably 0.5 to 1.0 μm. If the thickness of the primer layer is less than 0.2 μm, cohesive failure, which is the effect of the present invention, does not occur and 1.5
When the thickness is more than μm, the total thickness of the thermal transfer recording medium increases, the rigidity increases, and the recording medium becomes brittle, so that the ink layer easily falls off.

The ink layer of the present invention comprises a conventionally known heat-fusible layer and contains colorants, waxes and resins as main components.

In order to transfer the ink layer with lower energy, it is desirable to provide an overcoat layer on the ink layer. As the overcoat layer, waxes such as carnauba wax, paraffin wax, and beeswax and thermoplastic resins such as polyethylene, polyamide, polyester, ketone resin, and acrylic resin can be used, and coloring such as pigments and dyes can be used. Agents, fillers, etc. can also be added.

On the side of the support on which the ink layer is not formed, a heat resistant slipping layer can be formed to prevent sticking and to obtain smooth running. As a material for the heat resistant slipping layer, for example, a resin having excellent heat resistance such as silicone resin, fluororesin, or nitrocellulose, or a material containing a lubricant such as silicone oil or fluorine powder can be used. .

[0017]

In the present invention having such a structure, the ply is
The mer layer contains a caprolactone-based oligomer,
The number average molecular weight of the kutonic oligomer is 8,000 to 100.
Since it is 00, the adhesive force between the support and the ink layer is increased, so that even if wrinkles or folds occur on the support when the thermal transfer recording medium is mounted on the printer, the ink layer does not fall off. .

On the other hand, the caprolactone oligomer contained in the primer layer of the present invention has a melting point (40 to 60 ° C.) near the temperature of the thermal head and its vicinity when the support and the ink layer are peeled off after thermal transfer, and Since the molecular weight is in the oligomer region of 8000 to 10000, the internal cohesive force is lowered during printing in a high speed or high temperature atmosphere. As a result, the primer layer causes cohesive failure with a slight force, and the ink layer Since the support is peeled off smoothly, clear printing is possible.

When the caprolactone-based oligomer is contained in the primer layer in an amount of 30% or more, the ink layer is surely prevented from falling off from the above-mentioned support, and the primer layer is cohesively destroyed at the time of thermal transfer to make it clear. Printing can be performed.

In particular, the primer layer should contain a thermoplastic material selected from the group consisting of polyester resin, acrylic resin, terpene resin, styrene resin, rosin resin, petroleum resin and rubber resin. This makes it possible to prevent the foil of the ink layer from falling off in addition to adjusting the viscosity of the primer layer.

In particular, the primer layer contains a thermofusible substance selected from the group consisting of carnauba wax, candelilla wax, polyethylene wax, paraffin wax, microcrystalline wax, fatty acid ester and fatty acid amide, whereby the primer is In addition to adjusting the viscosity of the layer, the transferability can be improved without lowering the melting point of the ink layer.

The thickness of the primer layer is 0.2 to 1.5 μm.
Within this range, the rigidity of the thermal transfer recording medium does not increase, foil drop of the ink layer from the thermal transfer recording medium is prevented, and cohesive failure occurs in the primer layer during thermal transfer, enabling clear printing. To do.

The thickness of the primer layer is 0.5 to 1.0 μm.
By setting the range to, it is possible to more reliably prevent foil drop of the ink layer from the thermal transfer recording medium, and to cause cohesive failure in the primer layer during thermal transfer to enable clear printing.

When a heat resistant slipping layer is provided on the other surface of the support constituting the thermal transfer recording medium, sticking is prevented,
It is possible to drive smoothly.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to specific examples.

[Example 1] Formation of primer layer Number average molecular weight of 10 as a caprolactone-based oligomer
000 caprolactone oligomers (manufactured by Daicel Chemical Industries)
Praxel HI-P) 90 parts by weight of toluene which is a volatile solvent was added to 10 parts by weight of the volatile solvent and dissolved, and then a heat-treated polyester film having a thickness of 6 μm (manufactured by Teijin Limited) was subjected to a gravure coater. Was applied and the toluene was evaporated to give a dry coating. The coating thickness after evaporation of toluene was 1 g / m ² .

Formation of Ink Layer Next, 8 parts by weight of carnauba wax (Carnauba No. 2 manufactured by Noda Wax Co.) 8 parts by weight of paraffin wax (HNP-3 manufactured by Nippon Seiro Co., Ltd.) 1 part by weight of ethylene / vinyl acetate copolymer ( KA-31 manufactured by Sumitomo Chemical Co., Ltd.) 3 parts by weight of carbon black (MA-100 manufactured by Mitsubishi Kasei) was dissolved and dispersed in 80 parts by weight of toluene, and then applied on the front and rear primer layers by using a gravure coater, and toluene. Was evaporated to form a dry coating film, and a desired thermal transfer recording medium was prepared. Coating thickness after evaporation of toluene is 3g / m ²
Met.

Evaluation Method Each of the obtained thermal transfer recording media was evaluated under the following conditions.

1. When the printing speed is 2.3 inches / sec, a bar code printer (Model name BC-8 MK-II) manufactured by Autonics, 6
At the time of inch / sec, a bar code printer manufactured by SATO (model name M-8450) was used.

2. Ambient temperature When the printing speed is 2.3 inch / sec, the ambient temperature (2
Evaluation was performed at both temperatures of 5 ° C.) and 40 ° C. When the printing speed was 6 inches / sec, evaluation was performed only at room temperature (25 ° C.). In this case, each temperature means a temperature around the printer when printing is continuously performed.

3. Evaluation item (1) When the clear printing was performed without sticking, jerk, and tailing, it was evaluated as ◯, and when not, it was evaluated as x. (2) The surface of the printed matter was visually observed to observe the gloss state of the printed matter. If the primer layer is cohesively destroyed, the surface will be matte. The evaluation results are shown in Table 1.

Example 2 In forming a primer layer, a number average molecular weight of 10,000
7 parts by weight of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) was mixed with 3 parts by weight of the caprolactone oligomer (Placcel HI-P manufactured by Daicel Chemical Co., Ltd.), and 90 parts by weight of methyl ethyl ketone as a volatile solvent was added and dissolved. . After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 In forming a primer layer, a number average molecular weight of 10,000
7 parts by weight of carnauba wax (Carnauba No. 2 manufactured by Noda Wax Co., Ltd.) was mixed with 3 parts by weight of the caprolactone oligomer (Placcel HI-P manufactured by Daicel Chemical Co., Ltd.), and 90 parts by weight of toluene was added and dissolved. Hereinafter, Example 1
A desired thermal transfer recording medium was prepared in the same manner as in (1). Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 In the formation of the primer layer, 6.6 parts by weight of caprolactone oligomer (Plaxel HI-P manufactured by Daicel Chemical Co., Ltd.) and 3.3 parts by weight of caprolactone diol (Placcel 240 manufactured by Daicel Chemical Co., Ltd.) were used. That is, 2: 1
90 parts by weight of toluene was added to and dissolved in 10 parts by weight of a caprolactone-based oligomer having a molecular weight of 8000. After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Reference Example 1 In forming a primer layer, a number average molecular weight of 2,000
Caprolactone diol ( Praxe manufactured by Daicel Chemical Industries , Ltd.
90 parts by weight of Toruell was added to 10 parts by weight of the resin 220 ) and dissolved. After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Reference Example 2 In the formation of the primer layer, 90 parts by weight of toluene was added to 10 parts by weight of caprolactone diol having a number average molecular weight of 4000 (Placcel 240 manufactured by Daicel Chemical Co., Ltd.) and dissolved. After that, the target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Reference Example 3 In the formation of the primer layer, 90 parts by weight of toluene was added to 10 parts by weight of caprolactone triol having a number average molecular weight of 2000 (Placcel 320 manufactured by Daicel Chemical Industries) and dissolved. After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

[Reference Example 4] In the formation of the primer layer, 3 parts by weight of caprolactone diol having a number average molecular weight of 2000 (Placcel 220 manufactured by Daicel Chemical Industries) was mixed with 7 parts by weight of carnauba wax (Carnauba No. 2 manufactured by Noda Wax Co., Ltd.). Then, 90 parts by weight of toluene was added and dissolved. After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 In forming the primer layer, 98 parts by weight of toluene was added to 2 parts by weight of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) and dissolved. After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

[Comparative Example 2] In the formation of the primer layer, 9 parts by weight of carnauba wax (Carnauba No. 2 manufactured by Noda Wax Co.) and 1 part by weight of ethylene vinyl acetate copolymer (KA-31 manufactured by Sumitomo Chemical Co., Ltd.) were blended. Then, 90 parts by weight of toluene was added to 10 parts by weight of this formulation and dissolved. After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 In forming the primer layer, the number average molecular weight was 10,000.
90 parts by weight of toluene was added to and dissolved in 10 parts by weight of a caprolactone oligomer of 0 (Placcel H7 manufactured by Daicel Chemical Industries, Ltd.). After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4 In the formation of the primer layer, 6.6 parts by weight of caprolactone oligomer (Plaxel HI-P manufactured by Daicel Chemical Co.) and caprolactone oligomer (H manufactured by Daicel Chemical Co., Ltd.
4) To 90 parts by weight of toluene was added and dissolved in 10 parts by weight of a caprolactone-based oligomer having a number average molecular weight of 20,000 consisting of 3.3 parts by weight (that is, blended in a ratio of 2: 1). After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 5 In forming the primer layer, the number average molecular weight of 40,000 was used.
90 parts by weight of toluene was added to 10 parts by weight of the caprolactone oligomer (Placcel H4 manufactured by Daicel Chemical Industries, Ltd.) and dissolved. After that, a target thermal transfer recording medium was prepared in the same manner as in Example 1. Then, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 1.

[0044]

[Table 1]

As is clear from Table 1, the number average molecular weight is 8
000 to 10,000 of the caprolactone-based oligomers used in the primer layers of Examples 1 to 4 perform clear transfer without sticking, jerk, or tailing, regardless of changes in printing speed and ambient temperature. I was able to. Further, it was found that the surface of the printed matter was matte and the primer layer was cohesively destroyed. As shown in Table 1, when the number average molecular weight is 8000 to 10000, the peak of the melting point is 1 point, and very sharp responsiveness can be realized. On the other hand, when the number average molecular weight is less than 8,000, the melting point has a slight range. Therefore, in the qualitative evaluation, ◯ is given in all cases, but a more preferable result is obtained with a number average molecular weight of 8,000 to 10,000.

On the other hand, Comparative Examples 1 and 2 in which a caprolactone oligomer having a number average molecular weight of 10,000 or less is not used in the primer layer and Comparative Examples 3 to 3 in which a caprolactone oligomer having a number average molecular weight of more than 10,000 is used in the primer layer
No. 5 could not perform good printing in any of the above cases.

[0047]

According to the present invention as described above, according to the present invention, plug
The immer layer contains a caprolactone-based oligomer,
The lactone oligomer has a number average molecular weight of 8000 to 10
Since it is set to 000, it is possible to perform smooth and clear printing even in a high-speed and high-temperature atmosphere, and as a result, it is possible to provide a thermal transfer recording medium compatible with a printer that performs printing in a wide range of conditions. it can.

The number average molecular weight of 8000 to 8000 in the primer layer.
By containing 10,000 caprolactone-based oligomers in an amount of 30% or more, the above effect can be reliably obtained.

By including a thermoplastic substance and / or a heat-melting substance in the primer layer, the viscosity of the primer layer can be properly adjusted, and in addition, foil peeling of the ink layer can be prevented or / Also, the transferability can be improved without lowering the melting point of the ink layer.

The thickness of the primer layer is 0.2 to 1.5 μm.
m, preferably in the range of 0.5 to 1.0 μm, to prevent foil drop of the ink layer from the thermal transfer recording medium, and to cause cohesive failure of the primer layer during thermal transfer for clear printing. Can be made.

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Claims (7)

(57) [Claims] 1. A support, a primer layer provided on the support, and a heat-meltable ink layer provided on the primer layer , wherein the primer layer is a caprolactone-based material.
Including an oligomer, the caprolactone-based oligomer is
A thermal transfer recording medium having a number average molecular weight of 8,000 to 10,000 . 2. The thermal transfer recording medium according to claim 1, wherein the caprolactone-based oligomer is contained in the primer layer in an amount of 30% or more. 3. The other thermoplastic material contained in the primer layer is selected from the group consisting of polyester resin, acrylic resin, terpene resin, styrene resin, rosin resin, petroleum resin and rubber resin. The thermal transfer recording medium according to claim 1 or 2, characterized in that: 4. The other heat-fusible substance contained in the primer layer is selected from the group consisting of carnauba wax, candelilla wax, polyethylene wax, paraffin wax, microcrystalline wax, fatty acid ester and fatty acid amide. The thermal transfer recording medium according to claim 1, 2, or 3. 5. The thickness of the primer layer is from 0.2 to
2. The range of 1.5 μm.
2. The thermal transfer recording medium according to 2, 3 or 4. 6. The primer layer has a thickness of 0.5 to
2. The range is 1.0 μm.
2. The thermal transfer recording medium according to 2, 3 or 4. 7. A heat-resistant slip layer is provided on the other surface of the support, and the support is provided in any one of claims 1, 2, 3, 4, 5 and 6.
The thermal transfer recording medium according to.